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Re: [Xen-devel] HPET enabled in BIOS, not presented as available_clocksource -- config, kernel code, &/or BIOS?

From Andrew Cooper <andrew.cooper3@citrix.com>
Newsgroups linux.kernel
Subject Re: [Xen-devel] HPET enabled in BIOS, not presented as available_clocksource -- config, kernel code, &/or BIOS?
Date 2017-05-13 22:00 +0200
Message-ID <tGLmN-88a-5@gated-at.bofh.it> (permalink)
References (1 earlier) <tGJkZ-6O2-9@gated-at.bofh.it> <tGJXH-7hM-3@gated-at.bofh.it> <tGKTM-7SS-15@gated-at.bofh.it> <tGLd8-82A-9@gated-at.bofh.it> <tGLd8-82A-7@gated-at.bofh.it>
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On 13/05/2017 20:49, PGNet Dev wrote:
> On 5/13/17 12:38 PM, Andrew Cooper wrote:
>> What is the issue here?
>>
>> Xen owns (and may use) any HPETs in the system.  They are purposefully
>> unavailable to even dom0.
> The issue is that, when booting to Xen, hpet is not advertised as an available clocksource, AND reports the hpet boot error pointed out by Randy.
>
> Following 
>
>   https://wiki.xen.org/wiki/Xen_power_management#HPET_as_broadcast_timer_source_.28clocksource.29_.3D
>
> there's discussion there re: 'if HPET is available / not missing'.
>
> It appears to be available only booting to non-Xen.
>
> What specific indication does one look for that Xen's using available hpet?
>

Ok.  Lack of a clocksource is to be expected.

The reason why the HPETs are unavailable is that dom0 is not a position
to program them; dom0 doesn't know what Xen has set up in the IDT.

Use `xl dmesg` to get to the hypervisor dmesg log.  You should see
mention of the HPET in there if Xen has found it.

~Andrew

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HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 04:40 +0200
  Re: HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? Randy Dunlap <rdunlap@infradead.org> - 2017-05-13 19:50 +0200
    Re: HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 20:30 +0200
      Re: HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? Randy Dunlap <rdunlap@infradead.org> - 2017-05-13 21:30 +0200
        Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 21:50 +0200
          Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Andrew Cooper <andrew.cooper3@citrix.com> - 2017-05-13 22:00 +0200
            Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 22:10 +0200
              Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Andrew Cooper <andrew.cooper3@citrix.com> - 2017-05-13 22:20 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 23:10 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Juergen Gross <jgross@suse.com> - 2017-05-14 19:20 +0200
              Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Valentin Vidic <Valentin.Vidic@CARNet.hr> - 2017-05-13 22:30 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 23:10 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Valentin Vidic <Valentin.Vidic@CARNet.hr> - 2017-05-13 23:40 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-14 00:00 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Valentin Vidic <Valentin.Vidic@CARNet.hr> - 2017-05-14 00:20 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-14 01:20 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Andrew Cooper <andrew.cooper3@citrix.com> - 2017-05-14 17:50 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Randy Dunlap <rdunlap@infradead.org> - 2017-05-14 19:50 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2017-05-15 20:10 +0200
                Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-17 02:20 +0200
        Re: [Xen-devel] HPET enabled in BIOS, not presented as  available_clocksource -- config, kernel code, &/or BIOS? Andrew Cooper <andrew.cooper3@citrix.com> - 2017-05-13 22:10 +0200
    Re: HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? PGNet Dev <pgnet.dev@gmail.com> - 2017-05-13 22:00 +0200
    Re: HPET enabled in BIOS, not presented as available_clocksource --  config, kernel code, &/or BIOS? Clemens Ladisch <clemens@ladisch.de> - 2017-05-13 22:00 +0200

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